Free weight devices, including for example dumbbells, barbells, curl bars, and the like are well known in the art and are widely used as part of many weight-based exercise sessions. Free weight devices may allow a user to secure a desired amount of weight to the free weight bar. Exercise sessions using free weight devices often involve performing a number of repetitive movements while holding the weight bar. Exercise sessions using free weight devices often require an individual to track the number of repetitive movements (or “repetitions”) that are required to complete the session. Form and technique are very important in order to ensure that the proper muscle groups are targeted and to avoid injury.
Mechanisms exist that assist individuals in keeping a correct count of the number of repetitions performed. For example, U.S. Pat. No. 6,251,048, U.S. Patent Application Publication No. 2007/0135264, U.S. Patent Application Publication No. 2008/0204255, U.S. Patent Application Publication No. 2009/0069722, and U.S. Patent Application Publication No. 2011/0112771 each disclose devices that track and measure movements, such as repetitions performed, and transmit this information to an external computing device. These devices may be integrated into an article of clothing worn by an individual, such as a glove, or affixed to a part of an exercise device, such as a weight plate or a free weight handle assembly. Integrating these mechanisms into an article of clothing that is worn by an individual or affixing these mechanisms to an outer surface of an exercise device may cause an interference with the individual's exercise session. For example, the device may preclude the individual from gripping the exercise device in a desired location. In addition, the device may limit an individual's range of movement.
Also, these devices, whether integrated into an article that is worn by an individual or affixed to an outer surface of an exercise device, may track and measure movement that is unrelated to the exercise session. For example, a mechanism that is affixed to a weight plate on a free weight device may track movement of the plate relative to the bar. Specifically, the plate may rotate relative to the bar during an exercise session. This rotation may create errors in the data collected.